The present invention relates to a telephone apparatus, and particularly to an improved locking arrangement for a handset suitable for use in an environment where the telephone apparatus is subject to vibration, impact or the like. An example of such a telephone apparatus is a mobile radio telephone apparatus.
A telephone apparatus which is subject to vibration, impact or the like is required to securely hold the handset on the base unit. If the handset is detached from the base unit, the telephone apparatus will be in the state of hook-on so that reception is disabled. Moreover, the detached handset may collide with some other structure and may be damaged. In addition, it may form an obstacle to the proper operation of the vehicle. Another consideration is that the handset must be lifted off and mounted onto the base unit, usually by a single hand and by a simple manipulation. This requirement is particularly important in connection with a mobile telephone apparatus.
Examples of solutions to those problems are disclosed in the U.S. Pat. No. 4,117,276 and the British patent Application Publication No. 2,150,396.
Here, the U.S. Pat. No. 4,117,276 is taken as an example and is discussed. The telephone apparatus disclosed in this patent is shown in FIGS. 2 and 3. For mounting the handset 1, the heel (transmitter part) of the handset 1 is inserted in a recessed part 3 of a base unit 2, and then the head (receiver part) of the handset 1 is inserted into a recessed part 4. As the head is inserted, a boss 6 of a lever 5 is pushed. When the head has been inserted, the boss 6 slides into a recess in the head.
The lever 5 is pivotally mounted at a pivot point 7. When the boss 6 is pushed, the lever 5 is rotated in the direction of the arrow A and causes a second lever 9 to rotate about a pivot 10, the second lever 9 being connected to the lever 5 via a link bar 8. The second lever 9 is biased by a coil spring 13 (FIG. 2) in the direction of the arrow B (FIG. 3). By this biasing force, the boss 6 slides into the recess in the head.
To detach the handset 1, a button 12 is pushed, to rotate the lever 9, coupled via a spring 11 to the button 12, in the direction opposite to the arrow B, and thereby to rotate the lever 5 in the direction of the arrow A, so that the boss 6 is retracted. As a result, the recess in the head is released from the boss 6, so that it is now possible to lift the handset off the base unit.
However, the above-described telephone apparatus has a disadvantage in that it is necessary to lift the handset while pushing the button 12, so that handling or manipulation is difficult. Another disadvantage of the prior art telephone apparatus is that the locking mechanism is complicated.
Another prior art telephone apparatus as disclosed in the British Patent Application Publication No. 2,150,396 has similar problems.